Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is having trouble with the signal it gets when you put the car in reverse gear. It's like when a light switch doesn't work properly and the light won't turn on.
The P0812 code is triggered when the transmission control module (TCM) detects an issue with the reverse gear input circuit. This could be due to an electrical fault or a problem with the sensor.
The P0812 code indicates that the TCM has identified an irregularity in the reverse input circuit. This circuit is responsible for communicating the position of the reverse gear to the TCM. If the circuit is open, shorted, or otherwise malfunctioning, the TCM will set this code.
• Check Engine Light illuminated
• Transmission not shifting into reverse
• Erratic shifting behavior
• Faulty reverse gear position sensor
• Damaged wiring or connectors in the reverse input circuit
• Faulty transmission control module (TCM)
TCM: Transmission Control Module
OBD-II: On-Board Diagnostics II
• Check for any additional codes and address them first.
• Inspect the wiring and connectors related to the reverse input circuit for damage or corrosion.
• Test the reverse gear position sensor for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the reverse gear position sensor if faulty.
• Replace the TCM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$100 - $500
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect and maintain transmission wiring.
• Ensure connectors are clean and secure.
• Perform regular transmission services.
Transmission Issue
• Have the vehicle inspected by a professional mechanic.
• Avoid driving the vehicle until the issue is resolved to prevent further damage.
Check with the vehicle manufacturer for warranty coverage on transmission components.
The P0812 code has been associated with issues in vehicles with automatic transmissions, particularly in models with electronic transmission control systems.
Moderate – It is advisable to address this issue soon to avoid potential transmission damage.
Driving with a malfunctioning transmission can be dangerous. Ensure repairs are made promptly to maintain vehicle safety.
• Vehicle in park or neutral
• Engine running
The reverse gear position sensor is typically located on the transmission housing.
Q: Can I drive with a P0812 code?
A: It's not recommended to drive with a P0812 code, as it may lead to further transmission damage or unsafe driving conditions.
Q: How do I clear a P0812 code?
A: After repairs are made, the code can be cleared with an OBD-II scanner.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.